Impossible data usage

I have been a customer with autopage for many years! I am VERY disappointed in their service and billing! I received a debit order of R5700??? I phoned and asked for a breakdown of my account, that was on the 1st of May, i phoned again on the 4th asking for a breakdown, but nothing as yet! I was told the reason for this ridiculous amount was DATA USAGE?? I have 3 accounts, I also get free data on my phone and Ipad. Never, before had I use so much data, Then I was told on the 4th, to switch of my data on my phone??Okay..so why are you taking data if im not using it? And also why can no one give me a proper explanation. Where have I gone wrong, I do not download stuff, i only use data if needed. And never before was this a problem. So ive logged a complaint at the complaints department, and received an email back I need to give mtn and autopage a letter to give permission for them to retrieve the data really?? And was told it would take up to 8 weeks..I have also read some of the complaints from other customers, and I am not the only one having this impossible billing account! So i have rep**** on the email giving to me, but only to receive a mail back this mail does not exist.